1. Field of the Invention
This invention relates to a conveying system for underground mining and more particularly to a system of conveyor sections movably supported at the mine roof and connected to the discharge end portion of the continuous mining machine and movable therewith to provide a continuous conveying path for moving dislodged material rearwardly from the mining machine.
2. Description of the Prior Art
In underground mining operations conducted particularly by the pillar method of mining, a main longitudinal entry or haulageway is developed in the mineral seam with a plurality of lateral crosscuts connecting the main entryway with parallel entryways. In this manner, a plurality of pillars are formed and serve to support the mine roof. The mining operation is conducted by a continuous mining machine which is operable to dislodge the solid material from the face and convey it rearwardly to a discharge portion of the mining machine where it is removed from the mine either by a track haulage system or a permanent fixed belt-type conveyor that is operable to convey the dislodged material from the crosscuts to the main entry. In the main entry the dislodged material is deposited onto a main haulage belt that transports the mined material out of the mine to the surface.
It is of primary importance that the conveyor system connecting the continuous mining machine to the main haulage belt transports the material at a rate corresponding to the capacity of the continuous mining machine to dislodge the material from the face. However, a problem is encountered in removing the mined material from the working face at a rate which permits the uninterrupted operation of the continuous mining machine. The interruption occurs due to the inability of conventional track or belt-type conveyor systems to remove the material from the crosscut where the continuous mining machine is operating to the main haulage belt. The problem becomes more acute as the continuous mining machine progresses further in a crosscut and along a curved path from the main haulage belt. Substantial reductions in the width of the haulageway occur, and the mined material must be moved along a curved path by the fixed haulage system.
One solution to the problem of maintaining a continuous rearward movement of the mined material from the continuous mining machine is the use of self-propelled haulage-type vehicles, such as shuttle cars, which shuttle back and forth from the working face to a fixed discharge station where the mined material is conveyed to the surface. In carrying out the mine operation using the shuttle car, the continuous mining machine must stop the dislodging operation during intervals in which a loaded shuttle car is moved from material receiving relation with the mining machine discharge boom and an empty shuttle car is moved into position under the discharge boom. Consequently, the continuous mining machine is not able to obtain maximum efficiency by employing shuttle cars to transport mined material from the mine face.
Another method for conveying material from a continually advancing mining machine is illustrated and described in U.S. Pat. No. 3,795,304 and employs a movable surge vehicle. The surge vehicle has a haulage compartment with an endless conveyor having a receiving end portion positioned in underlying relation with the mining machine conveyor and a discharge end portion. The conveyor of the surge vehicle moves the dislodged material rearwardly at a controlled rate within the haulage compartment to the discharge end portion from which the mined material is deposited onto the upper surface of a flexible belt conveyor having end portions wound on rotatable spindles. The length of the belt is controlled by the amount of flexible belt remaining coiled on the rotatable spindles. In this manner, the effective length of the conveying surface may be controlled and coordinated with the loading and unloading of the surge vehicle as the continuous mining machine advances into the face and dislodges material therefrom. It is a primary object of this invention that the surge vehicle control the rearward movement of mined material from the face as to maintain a continuous rearward movement of the material on the flexible conveyor without interrupting the mining operation. However, this arrangement of conveying material rearwardly from the continuous mining machine has limited capability to follow a curved conveying path.
An additional solution that has been proposed to maintain uninterrupted operation of the mining machine and continuous conveyance of the mined material from the mining machine to the main haulage belt is disclosed in U.S. Pat. No. 3,003,612 and includes an extensible conveyor that extends between the fixed conveyor and the working face. The continuous mining machine is connected by a conveying path to a fixed conveyor station in which the conveying path includes a plurality of mobile conveyor sections so connected that the material discharged at the end of one section overlaps the material receiving end of the adjacent section. Each section is supported by a pair of wheels and is joined by a coupling that permits both vertical and horizontal articulation of each section as it follows a curved path through the mine and over the uneven terrain of the mine floor. The receiving section of the conveying apparatus is secured to the continuous mining machine with the remaining intermediate sections connecting the receiving section with a material discharge section. The conveying apparatus progresses with the continuous mining machine to provide a continuous conveying path rearwardly thereof.
There is need for conveying apparatus in mining operations for continuously conveying discharged material from the mine face along a curved path and is movable through the haulageways of a mine so as to provide a continuous interrupted conveying surface for the transportation of the mined material from the mine face at the rate the material is dislodged to provide a continuous mining operation.